This application proposes to conduct a randomized, double blind, placebo-controlled laboratory study to examine whether guanfacine (GUA) decreases cocaine and nicotine craving, anxiety and stress related arousal in cocaine dependent, nicotine smoking (CD) individuals. In previous research we've shown that laboratory exposure to stress and drug cues increases drug craving and stress related arousal and both measures predict cocaine relapse outcomes. Alpha-2-adrenergic agonists such as lofexidine and guanfacine attenuate stress-induced reinstatement of cocaine-seeking behavior in cocaine experienced laboratory animals. In previous pilot studies, we've shown that lofexidine decreases stress and cue-induced opiate and cocaine craving and reduces negative affect and physiological arousal in opiate dependent individuals treated with naltrexone. It was also found to improve opiate abstinence rates and compliance with daily naltrexone regimen. Preliminary work with GUA 2 mg and 3 mg daily dosing versus placebo (PLA) showed positive results with respect to drug cue-induced and stress- induced drug craving, anxiety and stress-related arousal. Thus, in light of previous preclinical research and our clinical findings, we propose a 3-year study that will recruit 60 CD individuals to participate in a randomized, double blind, placebo-controlled 4-week inpatient laboratory study. The following specific aims will be addressed: (1) to evaluate the safety/tolerability of 2mg and 3mg daily of guanfacine in CD individuals;(2) to determine the dose-dependent effects of guanfacine on basal cocaine and nicotine craving, depressive symptoms and perceived stress scores in weekly assessments during the inpatient stay;(3) To determine the dose-dependent effects of guanfacine on cocaine craving, nicotine craving and mood following guided imagery exposure to stress, drug cue and combined stress+drug cue scenarios;and (4) to determine the dose-dependent effects of guanfacine on cardiovascular and catecholamine (norepinephrine and epinephrine) response following exposure to stress, drug cue and combined stress+drug cue scenarios. Findings from this study will provide important information on whether alpha-2adrenergic compounds such as guanfacine show promise in decreasing drug craving, anxiety and stress, factors shown to predict high cocaine relapse outcomes. If the proposed hypotheses are supported, it will also provide evidence for further development of guanfacine as a medication for cocaine relapse prevention. PUBLIC HEALTH RELEVANCE: Drug craving and associated high cocaine relapse rates are major clinical challenges in the treatment of cocaine dependence, and drug craving, anxiety and stress-related arousal are significant factors that increase cocaine relapse risk. The proposed study will test guanfacine as a potential therapeutic strategy to decrease these symptoms of drug craving, anxiety and distress and cocaine relapse risk and the results will have significant clinical implications for the development of new medications to decrease cocaine craving and prevent relapse in cocaine dependence.